President Susilo Bambang Yudhoyono visited survivors camping out near the damaged Prambanan Hindu temple complex and pledged that food and medical aid would reach them soon.

"We are giving priority to the victims -- those who are injured, the sick, those who need surgery and also refugees who lost their homes and other belongings," he told reporters at the compound, a UNESCO heritage site.

"We are prioritising the medical treatments to save as many lives as possible," the president added later as he toured a makeshift camp in hard-hit Klaten district east of ancient Yogyakarta city.

The Indonesian army deployed at least 2,000 soldiers to assist with relief efforts, Army Chief General Joko Santoso said.

Australia ordered more than 80 disaster experts and medical personnel to the worst hit areas around Yogyakarta, in what Foreign Minister Alexander Downer characterised as part of "a hugely expanded emergency response".

The UN's World Food Programme (WFP) expected to ferry in more than 40 tons of supplies on Tuesday, including seven tons of emergency rations and four portable warehouses to store food, spokesman Barry Came told AFP.

Shipments also included tents, blankets, portable water treatment units and generators as aid flowed in from around the world.

The UN set up a coordination centre at Yogyakarta airport to organise the flow of help.

But some victims grumbled relief was too slow and too meagre.

In Klaten and throughout badly-damaged Bantul district, beggars held cardboard boxes daubed with the words, "Asking for aid".

"If we don't, how do we get money?" asked Budi, 18, whose box was empty as he waited for donations with a handful of other young men.

"Yesterday we got 40,000 rupiah (4.35 US dollars)," which villagers spent on cooking oil and food, said Wawan, 28, adding that government aid of three packets of instant noodles per family was not enough.

But the beggars slowed relief efforts as they put chairs, oil drums and stones in the road to slow drivers and ask for money.

A stream of aid trucks was caught in a major traffic jam on the main highway, stretching some 10 kilometres (six miles), the Detikcom online news service reported.

Hospitals were anxiously waiting for more medical staff and supplies to treat the thousands of injured who overflowed from their wards, raising fears of the spread of disease in the wet and poor sanitary conditions.

Indonesia has struggled to cope with the scale of the disaster, as Yudhoyono acknowledged Monday.

The social affairs ministry said 5,427 were confirmed to have died in the quake with some 20,000 injured. The Red Cross said 200,000 were homeless.

Adding to concerns was increased volcanic activity at Mount Merapi, to the north of Yogyakarta, which belched heat clouds and sent trails of lava running down its slopes, heightening fears of an eruption.

Plumes of smoke rose some 900 metres (3,000 feet) into the air -- nearly double the height of the previous day -- and the area remained on high alert.

Scientists have warned that although the magma flow which forms a dome at the peak appeared to be weakening, the structure may collapse and spew out millions of cubic metres of rock and lava.

"Theoretically as well as statistically, there is a very large possibility that tectonic activities trigger or increase volcanic activities," Syamsulrizal, who works at Indonesia's national vulcanology office, told AFP.

The quake was Indonesia's third major disaster in 18 months, following the tsunami that killed 168,000 in Sumatra and another quake that killed more than 600 people in Nias last year.

Nearly one in five -- 947 -- of the bison herd were sent to slaughter this winter for fleeing Yellowstone's snow-covered high country for food outside the park in Montana where cattle graze.

Bison advocates are outraged by the slaughter, which is authorized under an agreement between Yellowstone National Park and Montana's Department of Livestock. But Montana ranchers say the buffalo endanger the state's prized brucellosis-free status, which allows producers to ship their cattle across state lines without testing.

Fresh on the heels of Montana's first bison hunt in 15 years, Gov. Brian Schweitzer has charged into the debate, aiming to broker a deal between ranchers and buffalo admirers.

Schweitzer wants to expand the range the herd may roam outside Yellowstone National Park and would pay ranchers not to graze their cattle on the same land. He also has proposed increasing hunting permits for buffalo to up to 500 annually from 50 to help cull a Yellowstone herd that last year numbered 4,900, a record high since it was established in the early 1900s.

"I'm trying to come up with a solution that actually makes sense," Schweitzer said.

The rancher-turned-governor is promoting his plan even as a government operation last week to push buffalo back into the park using a helicopter and ATVs stirred fresh discord.

COWBOYS VS NATURALISTS

There is no documented case of brucellosis transmission in the wild from bison to cattle, and most of the animals killed this winter were not tested for the disease. Elk in the Yellowstone area also carry brucellosis, but the popular game animal has not evoked the same ire in Montana's $1 billion livestock industry.

Ranchers want to see bison confined within Yellowstone's unfenced boundaries whatever the cost.

"We need to do whatever it takes in the state of Montana to make sure those (brucellosis) transmissions don't occur," said Jay Bodner of the Montana Stockgrowers Association.

By contrast, the activist Buffalo Field Campaign says Yellowstone's bison herd has already suffered "carnage."

"People should be very disturbed when the government comes in and starts executing wildlife," said Buffalo Field Campaign board member Scott Frazier.

The debate in America is mirrored in Canada, where officials are toying with killing off the 4,500 free-ranging bison at Wood Buffalo National Park because of the beef industry's fears about brucellosis.

Underlying the dispute about the Yellowstone herd is a perennial debate in the American West about public lands, pitting its cowboy culture against nature lovers.

The conflict is heightening even as tourism is eclipsing ranching as a leading economic engine and newcomers are flocking to the Big Sky State for its scenic beauty and abundant wildlife.

Cattle graze near Yellowstone mostly on federal acreage and Montana's ranchers fear the push to protect the park's bison is a thinly veiled attempt to drive them from that land.

"Some advocacy groups would like to see cattle off public lands and have it only used for wildlife," said Montana Department of Livestock Director Marc Bridges.

Bison advocates say the country's last wild herd cannot afford to be lost.

"But maybe the public would rather have snowmobiles in the park rather than bison," said wildlife biologist Mary Meagher, a critic of the bison-management plan who worked with the Yellowstone herd for 35 years.

"Many officials think the pollution is nothing for the Yangtze," Xinhua quoted Yuan Aiguo, a professor with the China University of Geosciences, as saying.

"But the pollution is actually very serious," it added, warning that experts considered it "cancerous.""

Industrial waste and sewage, agricultural pollution and shipping discharges were to blame for the river's declining health, experts said.

The river, the third longest in the world after the Nile and the Amazon, runs from remote far west Qinghai and Tibet through 186 cities including Chongqing, Wuhan and Nanjing and empties into the sea at Shanghai.

It absorbed more than 40 percent of the country's waste water, 80 percent of it untreated, said Lu Jianjian, from East China Normal University.

"As the river is the only source of drinking water in Shanghai, it has been a great challenge for Shanghai to get clean water," Xinhua quoted him as saying.

China is facing a severe water crisis -- 300 million people do not have access to drinkable water -- and the government has been spending heavily to clean major waterways like the Yellow, Huaihe and Yangtze rivers.

But those clean-up campaigns have made limited progress because of spotty regional enforcement. Toxic spills are common, the worst recently being in the Songhua river in the northeast which led to the taps of Harbin being turned off for days.

Despite immediate concerns for the cities along its banks, the Yangtze, along with the Yellow river, is earmarked for China's ambitious South-North water diversion scheme -- a plan to pump water from southern waterways to the parched north.

But environmentalists fear that unless local governments and industries start getting serious about cutting pollution, most of the water shipped north will not be fit to drink.

Most of the Yellow River, the second-longest in China and the cradle of early Chinese civilisation, is so polluted it is not safe for drinking or swimming, Xinhua news agency said in May last year.

"There is no evidence of an explosion associated with this event," the observatory said in a statement.

Clouds obscured the crater at the time.

"We don't know how much steam and how much ash," Cynthia Gardner, scientist in charge at the observatory, told The Columbian. "These are very short-lived events."

Lava has continued to push into the crater - most recently forming a sheer rock fin - since the 8,364-foot mountain reawakened with a drumfire of low-level seismic activity in September 2004.

The crater was formed by the volcano's deadly May 18, 1980, eruption that killed 57 people and blasted about 1,300 feet off the then-9,677-foot peak.

China, which is plagued by sandstorms every spring, has embarked on a campaign to plant billions of trees and says it is slowing the rate of desertification, but Brown said the problem was far from under control.

"Here and there are successful pilot projects, but overall we are not anywhere close to arresting this situation. The deserts are expanding," he said.

The number of livestock grazing had mushroomed since China began economic reforms in the late 1970s, and, with little management, the number of sheep and goats jumped to 339 million, compared with about 7 million in the United States.

China has also said the sheer size of its deserts mean it will never completely tame the sandstorms that this spring covered the capital in brown dust, and left skies a murky yellow.

The dust from storms originating in China has in the past been traced all the way to the United States and Canada, Brown said.

Sandstorms were this year exacerbated by droughts across northern and western China, that were also contributing to forest fires raging in Inner Mongolia and Heilongjiang that some 20,000 firefighters were struggling to control.

Desertification, which officials at China's State Forestry Administration say is causing direct economic losses of about 54 billion yuan ($6.7 billion) a year, was also not helped by poor management of water, Brown said.

Water tables were diminishing in north China, causing rivers and land to dry out and affecting grain harvests, especially of wheat, which is grown predominantly in the drought-stricken northern provinces.

China plans to pump water from southern rivers to the parched north in a project known as the South-North water diversion scheme, but Brown said he doubted the efficacy of the plan already hampered by pollution and lack of adequate waste treatment.

Floods, mudflows and landslides triggered by days of torrential rain in parts of south China have killed at least nine people in recent days.

In recent months, chikungunya virus has spread from Madagascar and several other islands in the southwest Indian Ocean to the Indian mainland, where hundreds of thousands have been infected.

In some areas, one-third of the population is showing symptoms: They include sudden fever followed by a crippling pain in the joints that can cause patients to curl up. Chikungunya is Swahili for "one who walks bent over."

There is no vaccine or treatment other than painkillers. Chikungunya is rarely fatal, but it has the potential to temporarily incapacitate.

"If you get a quarter or a third of the population infected, it's potentially catastrophic, not only for health care, but also for workforce implications," said Dr. Kevin Kain, a tropical disease specialist at Toronto General Hospital.

Two species of mosquito transmit the virus. The species aren't native to Canada but they do live in the southern United States.

"There is a possibility that this virus could spread and become a problem in other parts of the world, for example in the Americas' more tropical areas," Artsob said.

People who return to Canada with the virus are not a threat to others, health officials note.

They advise anyone planning to travel to the affected areas to protect themselves by wearing long-sleeved clothing and putting mosquito-repelling DEET on exposed skin.

The sugar maple was once the dominant species in the forests of southern Quebec. Norway maples are a more recent addition. The trees were planted on the streets of Montreal and Toronto during efforts to reforest the cities in the 1960s and '70s.

Norway maples are fast-growing, pollution-resistant trees that are now considered an invasive species in the Ontario and the U.S.

The two species look alike for most of the year.

But come fall, sugar maples turn red and orange while Norway maples turn yellow and ochre. That's one reason why the streets of Montreal put on a less-flamboyant show compared with the forests of the Laurentians or the Eastern Townships.

The shift in tree populations was first noticed by people working on Mount Royal.

That led the city to fund a tree census by Prof. Jacques Brisson of the Plant Biology Research Institute and graduate student Joëlle Midy. They aimed to determine the extent of the problem and to look for long-term solutions.

Among trees 10 years or older, 4,200 sugar maples and 1,200 Norway maples were found. But the ratio reversed in younger trees, with three times as many Norway maples found than sugar maples, the pair said.

Brisson recommends that workers on Mount Royal learn to recognize the two species, so they can remove seedlings of Norway maples.

Another possibility, he said, is to plant young sugar maples to ensure the species will continue to be part of the city's forest 50 years from now.

"We are still ... Trying to understand this change of color in the lake from blue to red," Geology and Mines Department Director Esline Garae told the news agencies in a telephone interview from the Vanuatu capital, Port Vila.

She said that two scientists on Ambae Island were monitoring Lake Vui as well as seismic activity on the 1,500-meter Mt Manaro.

"If the change of color ... Comes from new activity in the ground or just chemical change in the lake- these are two things I want to know from those guys before I can say anything" about the danger posed by the volcano, she said.

Mt Manaro last erupted in November 2005, forcing half the island's 10,000 inhabitants to evacuate their villages but causing no injuries. The eruption before that, in 1884, killed scores of villagers.

Three other volcanoes in Vanuatu- Lopevi, Yasur and a two-crater volcano on Ambryn island called Marum and Benbow- have spewed rocks, ash, smoke and steam over the south Pacific island nation in recent weeks.

However, activity has slowed in recent days, Garae said.

"People should be on the alert because any scenario is possible," said police commander Noaufal Boina, head of the Comoros national emergency center.

Vulcanologists said the activity remained confined to the Chahale crater which was not yet threatening to spill over but warned that Mount Karthala could still erupt in earnest with potential threats from lava, ash and poisonous gas.

Hamidou Nassor of the Mount Karthala National Observatory expressed concern about "possible explosions if the magma comes into contact with water."

While eyeing the mountain warily, villagers in the foothills of the volcano remained at home Tuesday and went about business as usual, as did residents of Moroni, just 15 kilometers (nine miles) away.

The 2,361-meter (7,746-foot) volcano on the main island of Grand Comore last erupted in November spewed huge plumes of ash that blanketed the isle and temporarily deprived its 250,000 inhabitants of potable water.

Last April, nearly 10,000 villagers living at the base of the mountain fled their homes after similar emissions of ash sparked widespread fears of drinking water contamination.

Mount Karthala last had a magma eruption in 1977, when lava destroyed the village of Singani, some 20 kilometres south of Moroni, and toxic gas was released into the air but did not cause any deaths.